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I cheated a little with this lab. I did the first few steps, and then my group project sort of took things over. The group project, however, is very similar in spirit to the lab. There's lots of analog input and variables and whatnot.

Step 1 (1mb avi)

I couldn't get my serial output to work so I used the flashing rate of an LED to measure the input from a pot.

Step 2

I got the serial output working (it was a wiring issue) and I was in business with a flex sensor.

Step 3 (.4mb avi)
another video (1.2mb avi)

Ok, here's were I start cheating. Our group project is to create a souped-up sound meter for a beer garden. The idea is that when the sound level gets too high, our system can warn the patrons, they quiet down, and beer gardens don't have to close early anymore.

In order to do this, we had to rig up a microphone up to our pic. This required us to make a pre-amp. I used a circuit from another ITP student's journal.

Here's what it looks like on the breadboard:

Then, we wired 7 LED's to create a level meter.

None of this was too hard to wire. However, the software was a bit more difficult. We found that the output from the pre-amp was erratic. Our first attempt to tame the signal was take the average of 100 samples. However, this resulted in a value that never fluctuated. Now what we do is take the maximum value of 100 samples and use that for our output. The results are consistent with noise levels.

Here's the code.

Now, what makes this different from a normal level meter that you would find on a stereo? Well, there is computational power available to us in that chip. With software, we can log noise levels over time. What we will do with this information is not clear at the moment.